This invention relates to a caged seal assembly that is floatingly movable within a trocar or like device and intended for use independently of, but preferably, in combination with another seal assembly, which is also floatingly movable within the trocar. As such, a variety of medical instruments can be utilized with the present invention, so as to introduce and/or access the body cavity of a patient, regardless of the fact that each instrument may have a differently sized outer diameter, which would typically fall into a range of generally about 5 mm to 12 mm. Moreover, the caged seal assembly is structured to automatically assume either a non-sealing orientation or a sealing orientation, dependent at least in part on the size of the instrument passing through the trocar assembly.
Laparoscopic surgery has become quite common in recent years as it generally avoids several significant drawbacks associated with previous surgical methods. Those methods involved the making of large incisions into a patient's body so as to give the surgeon clear and unobstructed visual access to the targeted organ(s) or anatomical tissue of the patient for the surgical procedure involved.
In stark contrast, the currently favored surgical technique of laparoscopy involves the forming one or more small entry sites in the patient's abdominal wall for accessing his or her body cavity, using a trocar or like device to provide a working channel, and performing surgery on the targeted organ(s) or tissue via a medical instrument inserted into the trocar or like device. Following this type of surgery, patients usually experience significantly less pain and recover much more quickly than when the older surgical methods were used, and as a result, the minimally invasive procedures of laparoscopy have become well accepted in the medical field.
The trocar used in performing laparoscopic surgery typically includes an elongated tube or cannula, and the formation of the small surgical entry site(s) usually involves the insertion of an obturator with a sharp distal tip within the trocar and then pushing through the abdominal tissues until the wall or thick lining of the abdominal cavity is punctured. There are other techniques for making what is known as this “first stick” that do not involve using an obturator with a very sharp tip, as these can inflict damage by inadvertently nicking or puncturing an organ during insertion. Regardless, once the abdominal cavity has been reached, the obturator is usually removed from the trocar cannula, whereupon the abdominal cavity is inflated with a suitable gas, such as carbon dioxide, to provide space within the abdomen for the surgery to take place. The trocar cannula or like device remains in place at the entry site(s) and functions as a working channel across the abdominal tissues and thick lining of the abdominal cavity, and into that cavity, such that relatively thin and long handled instruments, including forceps, scissors, retractors, dissectors, etc., as well as a tiny video camera and light source, which are all specifically designed for this purpose, may be inserted through the trocar, although there will often be more than one trocar in place during surgery. While positioned in a trocar, the chosen medical instruments are manipulated by the surgeon into contact with the patient's organ(s) or anatomical tissue involved in the procedure.
As noted above, during laparoscopy the patient's abdominal cavity is typically insufflated, usually by the attachment of a source of gas to the trocar assembly, which gas is forced under pressure into the accessed abdominal cavity. Once that cavity is inflated, it is important that the fluid pressure within the body cavity be maintained in order to provide the needed access to the internal organs, as well as adequate room for visual observation during the surgical procedure. Therefore, it is important to prevent the escape of pressurized fluid from within the body cavity, back through the cannula and/or housing associated with the trocar. This is commonly achieved by the use of valves or sealing mechanisms within the trocar, and both “septum” valves and “zero closure” valves are used for this purpose. For example, it is known to use “septum” valves located at the proximal end of the trocar, usually within the housing of the trocar, to form a seal around the outer surface of a medical instrument which has been inserted within the trocar. However, these types of seals will not usually prevent the escaping of gas once a medical instrument has been removed from the trocar. As such, it is also known to provide trocars with a “zero closure” valve to prevent gas from escaping when there is no medical instrument present within the trocar.
First, and as indicated above, laparoscopic surgery can involve a variety of medical instruments during any given surgical procedure and there are also a number of manufacturers of such instruments. Accordingly, among other things, the outer diameters of these medical instruments can and do vary. For example, it is quite common for the outer diameters of such medical instruments to vary within a conventionally current range from about 3 mm to 15 mm.
This fact, however, presents an obstacle for preventing the escape of gas by a septum-type valve because such valves typically accommodate and effectively seal against medical instruments having a comparatively small and relatively limited range of outer diameters. This limited effective dimensional range may cause some disruption in the performance of the surgery. For example, the septum valve seal will not perform adequately when a medical instrument having a smaller outer diameter than the set size offered by the septum valve must be used. During such an occurrence there is a strong possibility that some insufflation gas will escape thereby necessitating the abdominal cavity being inflated again. As another example, if a medical instrument having a much larger outer diameter which is beyond the size of the valve within the trocar, there may be an unacceptable drag or friction force exerted on the instrument during its insertion into or removal from the trocar and/or while its is being manipulated during surgery. Further, the septum valve may become ripped, torn or otherwise damaged, leading to a loss of insufflation gas and/or a need to replace the trocar, etc. during surgery.
Known attempts to solve these problems have resulted in the provision of attachment devices for the trocar, which provide another or supplemental septum valve to accommodate the use of medical instruments having differently sized outer diameters during surgery. However, such devices must still be manipulated and/or somehow attached to the trocar to permit use during surgery. The required manipulation of them also has a tendency to interrupt the surgical procedures, at least somewhat, and further, can prove to be cumbersome and/or challenging, especially if the hands of the medical personal are wet, bloodied, slippery, etc.
In addition and as also noted above, during at least some laparoscopic procedures the trocar remains inserted through the patient's abdominal wall and into the abdominal cavity, so as to act as the working channel into which the various medical instruments are inserted or removed. However, during such procedures, the trocars are often disposed or manipulated to assume various angles such as an angularly, off-set position relative to the trocar. As such, the instrument could well be disposed out of axial alignment with the central axis of the trocar housing, as well as any septum valve or other valve assembly associated therewith. Again, the undesirable result may be a disruption in the performance of the surgery. Further by way of example, known septum valves are commonly made of a very thin, flexible material which can be punctured or ripped when a medical instrument is inserted at a skewed angle. This, in turn, can result in the loss of insufflation gas during surgery and a resulting delay if the trocar must be replaced. Also, while a surgery is in progress the manipulation of medical instruments within the trocar has been known to cause the septum valves to become “egg-shaped” which also typically results in the loss of some insufflation gas. Despite the recognition of these and other disadvantages and problems and the numerous attempts to address them, there remains an appreciable need for an improved mechanism or assembly for sealing the outer surface of medical instruments used in trocars or like devices. Any such improved sealing mechanism should be suitable for and readily used with a trocar assembly or like device, and further, should effectively maintain insufflation pressure within a patient's body cavity, once it has been accessed and inflated. Any such improved sealing mechanism should also accommodate and/or facilitate the introduction of medical instruments into the trocar, even when oriented in an angular, off center orientation relative to the longitudinal axis of the trocar and/or the inlet port associated therewith, and should also resist the formation of ovals or “egg-shapes,” especially when the medical instrument is being forcibly manipulated and otherwise used during surgery.
Further, any such improved sealing mechanism should be structured to prevent or significantly reduce the possibility of damage thereto, especially when the seal assembly comes into contact with the distal end of a medical instrument being introduced. Any such improved sealing mechanism should also be capable of accommodating a number of medical instruments of various outer diameters, such as, but not limited to, those falling within a currently conventional range of about 3 mm to 15 mm. Ideally, any such improved sealing mechanism would also accomplish all of the foregoing without creating excessive drag or friction on the medical instrument while it is being inserted into or removed from a trocar or otherwise moved about during performance of a surgery.